Kubernetes Service

A Service in Kubernetes is associated with nursing abstraction that defines a logical set of Pods and a policy by that to access them. Services alter a loose coupling between dependent Pods. A Service is outlined exploitation YAML (preferred) or JSON, like all Kubernetes objects.

Kubernetes Service

Service without Selector

apiVersion: v1
kind: Service
metadata:
   name: salesforce_drillers_service
spec:
   ports:
   - port: 8080
   targetPort: 31999

Service Config File with Selector

apiVersion: v1
kind: Service
metadata:
   name: salesforce_drillers_service
spec:
   selector:
      application: "My Application" -------------------> (Selector)
   ports:
   - port: 8080
   targetPort: 31999

Here we have a selector, so in order to transfer traffic, we need to create an endpoint manually.

apiVersion: v1
kind: Endpoints
metadata:
   name: salesforce_drillers_service
subnets:
   address:
      "ip": "192.168.168.40" -------------------> (Selector)
   ports:
      - port: 8080

Here we have created an endpoint which will route the traffic to the endpoint defined as “192.168.168.40:8080”.

Multi-Port Service Creation

apiVersion: v1
kind: Service
metadata:
   name: salesforce_drillers_service
spec:
   selector:
      application: "My Application" -------------------> (Selector)
   ClusterIP: 10.3.0.42
   ports:
      -name: http
      protocol: TCP
      port: 80
      targetPort: 31999
   -name:https
      Protocol: TCP
      Port: 443
      targetPort: 31998

Types of Services

ClusterIP − It helps in restricting/limiting the service within the cluster. It exposes the service among the outlined Kubernetes cluster.

spec:
   type: NodePort
   ports:
   - port: 8080
      nodePort: 31999
      name: NodeportService

Cluster IP

NodePort − It will expose the service on a static port number on the deployed node. A ClusterIP service, to which NodePort service can route, is mechanically created. The services are often accessed from outside the cluster mistreatment the NodeIP:nodePort.

spec:
   ports:
   - port: 8080
      nodePort: 31999
      name: NodeportService
      clusterIP: 10.20.30.40

NodePort

Load Balancer −It uses cloud providers’ load balancer. NodePort and ClusterIP services square measure created mechanically so that the external load balancer can route.

A yaml file (full service) with service type as Node Port. Try to create one yourself.

apiVersion: v1
kind: Service
metadata:
   name: appname
   labels:
      k8s-app: appname
spec:
   type: NodePort
   ports:
   - port: 8080
      nodePort: 31999
      name: omninginx
   selector:
      k8s-app: appname
      component: nginx
      env: env_name

Load Balancer